Stack axle assembly and transporters having the same

ABSTRACT

A stack axle assembly as used in a cask transporter or an horizontal storage module (HSM) gantry transporter. The stack axle assemblies include a slew gear; an upper bearing; a lower bearing; a vertical cylinder retained by the slew gear, upper bearing and lower bearing; an independent driver wheel and idler wheel revolving on a common shaft/trunnion assembly attached to the bottom of the vertical cylinder; a frame assembly formed on top of the vertical cylinder, the frame assembly including one or more drive motors connecting an upper drive assembly downwardly to a driven assembly mounted between the idler wheel and driver wheel; and a slew driver motor to drive the slew gear.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a transporter to carry very heavyloads. More particularly, the present invention relates to a transporterwith single wheel power driven axle assemblies that haveomni-directional steering, fluid equalizing suspension, and on-centeraxle rotation capability in order to carry very heavy loads.

2. Description of the Related Art

A nuclear reactor operates by facilitating a controlled nuclear chainreaction in a reactor core. Typically, the nuclear reaction is fueled byan isotope of uranium, which is supplied to the reactor core in aplurality of elongated fuel rods, which are typically metallicstructures that are packed with uranium pellets.

When the fuel rods must be removed and replaced, the spent nuclear fuelis typically temporarily stored in water pools that dissipate generatedthermal energy and attenuates radiation emitted from the spent nuclearfuel. For long-term storage, the spent fuel rods are transferred toeither horizontal or vertical radiation shielded and ventilated concretecasks. The present invention deals with vertical-type cask systems.These casks used to store the spent nuclear fuel are vertical-standing,cylindrical, radiation-sealing concrete casks typically weighing atleast 150 to 200 tons. Once the spent nuclear fuel is in a cask, thecask needs to be transported from the nuclear refueling facility to anIndependent Spent Fuel Storage Installation (ISFSI). The ISFSI isdesigned for the long term storage of decaying radioactive materials.

Various options exist for transporting vertical-type casks both within anuclear refueling facility and from a nuclear refueling facility to anISFSI. These options include heavy multi axle specialized carriertrailers, industrial air cushion devices (so called “air bearings”),overhead cranes, and specialized vertical lift gantry frames attached toa crawler tractor bed assemblies. These options all have significantdisadvantages. For example, for vertical-type casks, heavy multi axlespecialized carrier trailers require an extended operating space and arenot capable of engaging and moving the casks out of the fuelbuilding(s), or of doing the actual positioning the cask in the closespacing requirements within the ISFSI. Removing the cask from the fuelbuilding typically requires some type floor level transfer capabilitysuch as industrial air cushion devices (air bearings), heavy capacityroller devices, or in-floor rails with low profile transfer cars. At theISFSI, final spacing is accomplished by transferring the casks from thetrailers by using industrial air cushion devices (air bearings) or heavycapacity roller devices. Furthermore, a disadvantage of air cushiondevices is that they require a large pressurized air supply and asmooth, non-porous surface in order to maintain lift and operateproperly. Moreover, specialized vertical lift gantry frames attached tocrawler tractor bed assemblies have the disadvantage of a large size,especially height, and a lack of maneuverability. The crawler treadstend damage operating surfaces when skid turning under these types ofloading conditions.

Another option for horizontal type spent nuclear fuel casks are InPlant-Self-Propelled Modular Transporters (IP-SPMT). An IP-SPMT refersto a low-profile deck, multi-axle, self-propelled transporter, withall-wheel drive independent suspension axle assemblies that aretypically used in combinations to carry loads heavier than 80 tons. AnIP-SPMT is typically internal combustion engine-electric powered and hassix to twelve or more on-center rotation axle assemblies. The axles canbe independently steered by varying each wheel motor speed anddirection.

However, in vertical-type spent nuclear fuel cask applications, existingIP-SPMT devices are not sufficient because of the need to pick and placethe vertical cask directly to or from the operating surface. One IP-SPMTdevice proposed by the inventor of the present application utilizesuniload axle assemblies as disclosed in U.S. Pat. No. 5,379,842, whereinthe axles assemblies are gear motor rotated for steering coupled withhydraulic differentially power driven wheels. Referring to FIG. 4, theuniload axle assembly 106 includes a drive motor 14 having mountedthereon a pinion gear 16 in mesh with a ring gear 18 which is bolted toa circular plate as explained hereinafter. The drive motor 14 is boltedto a piston top plate to which is secured a square machined upper shaft26 to transmit the torque from the top plate to the wheel set via asquare torque plate upper flange 28 which is sectional so that it may beremoved. A pair of wheels 34 are mounted to axles which form arelatively fixed part of wheel truck 38 which includes a yoke portion.Trunnions 42 are mounted on the sides of the bottom casing which housesa piston secured to the upper shaft 26. Ongoing design versions of thesame patent concept eliminate the gear motor steering for differentialsteering where all-wheels are electrically driven with computercontrolled differential steering.

Although the uniload axle assembly 106 disclosed in U.S. Pat. No.5,379,842 addresses the problem in the conventional art overloadingoperating surfaces, the disclosed uniload axle assembly 106 has a footprint too large for some applications, including vertical casktransportation.

Accordingly, what is needed is a heavy capacity self-loading transporterwith an on-center rotation independent axle assembly that is devoid ofscrubbing action while turning under full load so that casks can bemoved from nuclear refueling facilities having narrow entry ports andrestricted door heights to an ISFSI.

SUMMARY OF THE INVENTION

It is an aspect of the present invention to provide a stack axleassembly for use in a transporter, including a slew gear; an upperbearing; a lower bearing; a vertical cylinder retained by the slew gear,upper bearing and lower bearing; an independent driver wheel and idlerwheel revolving on a common shaft/trunnion assembly attached to thebottom of the vertical cylinder; and a frame assembly formed on top ofthe vertical cylinder. The frame assembly including a drive motor(s)connecting an upper drive assembly downwardly to a driven assemblymounted between the idler wheel and driver wheel.

The stack axle assembly may further include a slew driver motor to drivethe slew gear.

In the stack axle assembly, the upper bearing may include one or morekeyway slots that allow the vertical cylinder to travel vertically,while transmitting rotational torque force from the slew gear to thevertical cylinder.

In the stack axle assembly, the driver wheel may have a larger diameterthan the idler wheel to accommodate compression and expansion of thedriver wheel when encountering floor irregularities that would otherwisecreate uneven loading on the driver and idler wheels.

In the stack axle assembly, one wheel may be made of a softercompressive material than the other wheel.

It is a further aspect of the present invention to provide a casktransporter comprising a main body including a power compartment and aplurality of uniload axle or stack axle assemblies; two arms extendingfrom the main body, each of the arms including a plurality of stack axleassemblies; and protrusions are formed on the arms and main body toengage a cask.

In the cask transporter, the power compartment may include a powersource; a processor; an AC electrical panel; a display; and a hydraulicpower unit.

In the cask transporter, the uniload axle assemblies may include an axleframe including a cylinder housing and hydraulic piston; and two or morewide faced solid elastomeric wheels on opposing sides of the axle frame.The wheels on each end of the axle are independently driven by anelectric motor.

The stack axle supported portion of the design allows the structuralshape of the cask transporter to be much narrower than the currentcrawler gantry configurations thereby allowing the stack axle casktransporter to enter the narrower fuel building doorways that are commonin older nuclear plants. One disadvantage of the current crawler mountedgantries is that they require high doors, by their need to lift thecasks from the top. The configuration of the current crawler mountedgantries places a bridge beam and hoisting attachments that can extendseveral feet above the top of the casks. In many cases the crawlermounted gantries can not enter the fuel building and casks have to bemoved out of the building on air bearings, heavy roller devices, or sometype of in-floor rail system, before the crawler can engage and carrythem to the ISFSI; whereas, the stack axle cask transporter lifts thecask from the cask's bottom air vents and only need lift the cask a fewinches, just enough to clear undulations or obstructions on theoperating surface. In the case of entering or exiting the fuel building,the overhead door clearance need only be a few inches higher than thetop of the cask and stack axle's very narrow legs accommodate the oldernarrow entry doors. From a safety standpoint the cask is totally securedwithin the stack axle cask transporter's structure.

It is a further aspect of the present invention to provide rigidly fixedand forward extended pawls at the aft base of a U-shaped casktransporter which will engage two or more of the air vents in the bottomof the casks, while two clamps located high on the transporters armsextend and lock to bear solidly against the forward sides of the cask,locking the cask into the transporter and holding it in the uprightposition without possibility of tipping forward. In addition, twoself-locking toggle clamps provide backup support in the event of a mainclamp failure.

This engagement means the time and effort to engage and disengage fromthe casks are dramatically reduced. Also safety is greatly increased bynot requiring workmen to climb up high on top of the cask to positionand attach the heavy lifting gear as is currently necessary with thecrawler mounted gantries.

The narrow shape and omni-directional effortless maneuverability of thestack axle cask transporter dramatically increases the functionality ofthe system, particularly when placing casks in the narrow confines ofthe ISFSI storage pads. Those two factors, narrow shape andomni-directional maneuverability allow casks to be placed closertogether, and thereby reduce the acreage required for a new or expandedISFSI storage facility, which is an important factor for nuclear plantsthat have limited space.

In some applications that do not have crawler mounted gantries, acombination of air bearings, large mobile cranes, and low-boy heavy haultrailers are used to make the short trip from the fuel building to thestorage pads. In these cases the spent fuel filled casks are moved fromunder the overhead cranes inside the fuel building to the outside byeither air bearings, heavy roller-type devices, or in-floor rail mountedtransfer cars. Outside the building a heavy lift mobile crane will setthe cask onto a heavy-haul lowboy trailer. The trailer will be hauled tothe nearby ISFSI storage pads and positioned. The mobile crane will bemoved to the ISFSI and set up again at the storage pad site to lift thecask onto its storage pad location. In some cases, the storage pads areelevated to a height that is flush with the deck of the low-boy trailerand the cask are slid laterally from the trailer onto the storage padusing air bearings or heavy rollers. In the case of air bearings, safetyis a more predominant issue. If the storage pads are not dead level orappropriate side guide restraints are not in place there is the issue ofthe frictionless air bearings moving off the desired travel path andcrushing workmen between the moving load and an adjacent cask. With airbearings there are the issues of providing a smooth uninterruptedoperating surface and the positioning of a large portable air compressorand the handling of large diameter hoses connecting to the load.

According to the present invention, the self-propelled stack axle casktransporter engages and lifts the casks off the floor from inside thefuel building and is driven directly to the final ISFSI storage padlocation. The stack axle cask transporter's narrow shape and omnidirectional travel capability allows new or expanded ISFSI storage padsto have much narrowed alleys between single and double rows of storedcasks. With its omni directional travel capability, the stack axletransporter can rotate on-center and provide infinitely accuratemaneuvers in linear, lateral, or diagonal travel patterns to alloweffortless precision placement of casks in tight, and otherwisedifficult to access, storage locations.

Yet another aspect of the stacked axle technology is the adaptation intoa rigging gantry configuration. In the case of horizontal storagesystems, commonly known as “NUHOMS®”, horizontal storage modules (HSMs)are large rectangular concrete box-shaped structures that are typicallyplaced side by side in singular or double rows. The HSMs typically weighroughly 260,000 lbs when they are fully assembled, and ready to beplaced in the ISFSI. Currently, the heavy precast HSM components areshipped to the site on heavy haul trailers and must be assembled intheir final locations, which is a slow and labor intensive activityrequiring a large mobile crane. By adapting the stack axle technology,two multi-axle sill beams are interconnected at one end of the sill beamto provide a U-shaped structure. The interconnecting beam is raised inthe center to allow it to pass over the decks of heavy haul trailers.Some heavy haul trailers have “goose neck” connection of the ends of thetrailer deck. Wherein the trailer hydraulically lowers to the ground andone of the goose necks is removed to allow the transporter to centerover the load. The interconnecting beam is also designed with a boltedconnection to the sill beams, and a bolted center connection that willallow an intermediate beam to be bolted in place when a wider stance isrequired. The center of each sill beam is augmented with a hydraulicvertical telescoping gantry tower. The gantry towers are rigidly mountedto the sill beams and penetrate through to within a few inches of theground when the stack axles are in their lowest positions. A heavysection wide flange beam, known as a “bridge girder”, is mounted to thetop of the gantry towers.

Typically, when used in standard rigging gantry applications, there willbe two heavy steel plates with lifting eyes on the underside that aremanually positioned on the bridge to be above the points of lift. Inthis stack axle gantry configuration, these movable lifting devices willhave spring loaded rollers that, when not engaged with the load, allowthem to lift and carry the weights of the lifting devices and thespreader bar assembly. Each movable lifting device will have amonorail-type tractor running on top of the bridge girder. Thesetractors are operated from the operator's console, which is used toelectronically control all of the stack axle gantry's functionality.

The gantry will be used to assemble multiple HSMs in a staging areasomewhere in the proximity of the ISFSI. Components are carried on theincoming heavy haul trailers in the lengthwise orientation. The“spreader beam” for the gantry is actually a rectangular device that isdesigned to lift and carry either linear or laterally oriented loads. Inthe case of an HSM assembly, all assembly will be done with the linearconfiguration. When it is time to switch over to carry the fullyassembled HSMs, they have to be placed with the gantry in the lateralorientation. To accomplish this, the gantry moves over a raised platformand lowers the spreader beam onto the platform and disengages. Thegantry then backs away, moves 90 degrees to its current orientation andthen drives over the spreader beam from the new direction. The gantrylowers and engages the spreader from the new orientation to be able topick and carry the HSMs in the lateral orientation. As the gantry movesover the first HSM to be placed, the operator will activate the tractordevices as necessary to best place them over the proper points to pickup the HSM. The gantry will lower, and the lifting straps will bethreaded through the bottom air vents on the HSM, then lift the HSM fortravel to its next position point in a single or double rowconfiguration. In the single row configuration the gantry is straddlingjust one HSM.

However, for double row HSM assembly, the gantry will have beenconfigured to straddle two HSMs placed end to end. Since the gantry isdesigned to be disassembled for transport between jobsites, the gantrywould have been assembled with an extender beam placed in the centerbetween the two sill beams and a longer and heavier capacity bridge beamwould connect the two gantry towers. The heavy plate lifting devices andthe spreader beam will be free to move to the center or to one side orthe other of the bridge beam for first component assembly, and thenprecision placing the HSMs in either the left or right hand positions asthe double row moves forward. Typically six to eight or more HSMs areplaced in a single or double line row.

In this configuration, this type of gantry can become a valued tool forheavy riggers in general construction and plant assembly operation. Thesill beams containing the stack axles can contain multiple rows of stackaxles on each side, as well as designed with larger diameter barrels andwheels to accommodate virtually any capacity lifting requirement intothe 1,000 ton range and still have all of the dexterity of a single rowof stack axles.

The stack axle assemblies may include a slew gear; an upper bearing; alower bearing; a vertical cylinder retained by the slew gear, upperbearing and lower bearing; an independent driver wheel and idler wheelrevolving on a common shaft/trunnion assembly attached to the bottom ofthe vertical cylinder; a frame assembly formed on top of the verticalcylinder, the frame assembly including a drive motor(s) connecting anupper drive assembly downwardly to a lower driven assembly mountedbetween the idler wheel and driver wheel; and a slew driver motor todrive the slew gear.

In all transporter applications, the processor may include a multitudeof machine logic controllers to control each of the uniload axle andstack axle functions. The steering mode controller performs steeringalgorithm calculations for the plurality of axle assemblies to handlesteering functions linearly, laterally, diagonally, and rotationally, sothat all axle assemblies are controlled synchronously. A speed/directioncontroller provides command signals to the individual axle assemblies. Asuspension controller lifts and lowers the transporter and controls themean travel height.

In the cask transporter, the load relief controller may decrease fluidpressure to the cylinder housing of selected single or pairs of axleassemblies to transfer their load onto surrounding fully pressurizedcylinder housings in event of any single axle assembly malfunction.

In the cask transporter, the suspension controller may control fluidpressure acting on each of the hydraulic pistons of each of the axleassembly to provide interaction between multiple axle assemblies tonegotiate undulating surface irregularities along the line of travel ofthe transporter.

In the cask transporter, the AC (alternating current) electrical panelmay include a shore power connection as an alternate power source.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be apparentfrom the description, or may be learned by practice of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the invention will become apparent andmore readily appreciated from the following description of theembodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is side view of the a stack axle assembly according to anembodiment of the present invention;

FIG. 2A is a side view of a cask transporter according to an embodimentof the present invention;

FIG. 2B is a side view of a cask transporter according to an embodimentof the present invention;

FIG. 2C is a side view of a cask tilt restraint cylinder and back uptoggle links according to an embodiment of the present invention;

FIG. 2D is a side view of a preferred air vent engagement according toan embodiment of the present invention;

FIG. 3 is a control schematic of the cask transporter according to anembodiment of the present invention;

FIG. 4 is a perspective view of a uniload axle assembly according to theprior art, respectively;

FIG. 5A is a side view of stack axle transporter according to anembodiment of the present invention;

FIG. 5B is a perspective view of the stack axle transporter according toan embodiment of the present invention;

FIG. 5C is a side view showing the adaptation of the stacked axletechnology into a rigging gantry configuration according to anembodiment of the present invention;

FIG. 5D is a side view showing the adaptation of the stacked axletechnology into a single row gantry configuration according to anembodiment of the present invention;

FIG. 6 is a side view of the stack axle technology adapted into a doublerow gantry configuration according to an embodiment of the presentinvention;

FIGS. 7A-7D are side views of both truck off-load and HSM assemblyrigging gantry configurations according to an embodiment of the presentinvention; and

FIG. 8 is a top view showing the transporter having axles angled to thedirection of travel according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout.

FIG. 1 shows an stack axle assembly 10 according to the presentinvention that allows self-propelled, omni directional travel in a heavyload transporter, where each “single wheel” is actually an independentdriver wheel 12 and idler wheel 14 revolving on a common shaft/trunnionassembly 16, which is in turn attached to a open-center vertical risingcylinder 18 retained in a slew gear 20, upper bearing 22 and lowerbearing 24. On the top of said vertical rising cylinder 18 is a frameassembly 26 in which a drive motor 28 connects an upper drive assembly30 downwardly to a lower driven assembly 32 mounted between the idlerwheel 14 and driver wheel 12. Although one drive motor 28 is shown, morethan one drive motor may be employed with the present invention.Rotational torque for the on-center rotation of the stack axle assembly10 is accomplished with a slew driver motor 34, frame-mounted to contactthe top surface mounted combination of the slew gear 20 and bearings 22and 24. The upper bearing 24 is designed with one or more keyway slotsthat allow the cylinder 18 to travel vertically, while transmittingrotational torque force to the cylinder 18.

To assure that sufficiently equalized loading on individual stack axleassemblies 10 is being applied to both the driver wheel 12 and idlerwheel 14, the driver wheel 12 may have a different diameter andcompressive material than its companion idler wheel 14 to accommodatecompression and expansion of the wheels when encountering floorirregularities that would otherwise create uneven loading on the driverand idler wheels. When a load is applied to vertical cylinder 18, andthe wheels 12 and 14 are on a laterally uneven surface, the driver wheel12 may expand or compress to provide equalized loading across thesurfaces of both wheels 12 and 14.

The ability to use an idler wheel 14 and driver wheel 12 on a commonaxle as a power driven as well as fully steerable on-center rotationaxle assembly nearly eliminates rolling resistance due towheel-scrubbing as the axle rotates about its vertical axis. Each wheel12 and 14 is rotating about the axle's center, where the open spacebetween the wheel elements forms the center of rotation and is nottouching the operating surface. The natural tendency of a one-side-onlydriven dual wheel element to cause the axle to rotate only about itsvertical axis is offset by a keyed relationship with the power drivenslew gear 20 and bearing 22 that provides independent directionalsteering of each stack axle assembly 10.

To obtain assurance of equalized loading across a plurality ofinteracting stack axle assemblies 10, the weight of the load beingcarried is transmitted from the cask transporter's 100 (see FIG. 2A)carrier frame to each on-center rotation stack axle assembly 10 throughvertical mounted hydraulic cylinders 18 that are attached to trunnionmembers 28 on top of each of the open-center vertical rising cylinders18 frame assembly. The individual hydraulic cylinders 18 work in unisonand synchronous motion, via either group-exchange of oil betweencylinders or by computerized signal monitoring of individual hydrauliccylinder pressures through the use of pressure transducers in theindividual cylinders or zone groupings of axle cylinders.

Each of the stack axle assemblies 10 and uniload axle assemblies 106receives computer controlled steering commands that proportionallyassure that every axle is either parallel (for straight line travel) oreach axle is pointing at an exact single floating point of center ofrotation, typically, somewhere along the X or Y center centerline. Sucha point can be fixed in space (preprogrammed) for a transporter'srotation about any exact predetermined radius, or the point can “float”to allow random path precision steering in response to an operator'smovement of a joystick-type controller.

Referring to FIG. 2A, a plurality of the stack axle assemblies 10 may beadvantageously employed in a cask transporter 100 according to thepresent invention to achieve a very narrow profile cask transporter 100capable of effectively transporting spent nuclear fuel casks from anuclear refueling building to an IFSFI.

FIG. 2A shows a cask transporter 100 according to the present invention.The cask transporter 100 has essentially a U-shape and includes a mainbody 102 housing a power compartment 104 (as shown in FIG. 3), and aplurality of uniload axle assemblies 106. Essentially, the wide-facedelastomer wheels on the uniload axle assemblies 106 included areindependently functioning and independently powered to accommodatedifferential steering.

Extending from both sides of the main body 102 of the cask transporter100 are two arms 110. Housed within each of the arms 110 are a pluralityof stack axle assemblies 10. Pawls 112 are formed on the arms 110 andmain body 102 to engage a spent nuclear fuel cask 120, by entering intoand lifting on the lower air vents 207 of the concrete casks. Theembodiment of FIG. 2A shows two side-mount lifting pawls 112 for betterweight transfer in the cask 120 and the transporter 100.

The cask transporter 100 illustrated in FIG. 2A shows four uniload axleassemblies 106, although it is contemplated for the cask transporter 100to include more or less axle assemblies 106. Each of the uniload axleassemblies 106 has independent suspension, is capable of independentlyfunctioning in self-loading operations, and has on-center axle rotation.

The cask transporter 100 shown in FIG. 2A shows four stack axleassemblies 10 in each of the arms 110, although it is contemplated forthe cask transporter 100 to include more or less stack axle assemblies10.

By placing the stack axle assemblies in the arms 110, the framedimensions of the cask transporter 100 are as narrow as possible whichallows passage through narrow doors when entering nuclear refuelingbuildings 600. With its precision maneuvering capability the casktransporter 100 can function in a “creep speed” mode and smoothlymaneuver through spaces, such as narrow fuel build doors with onlyfractions of an inch clearance. Further, despite their narrow profile,the stack axle assemblies 10 provide equalized loading for travel overuneven roadway surface between the refueling building and ISFSI storagepads.

Referring to FIG. 2B, the central open portion of the cask transporter100 is dimensioned and configured to accommodate a spent nuclear fuelcask 120. Pawls 112 are formed on the arms 110 and main body 102 toengage the spent nuclear fuel cask 120, by entering into and lifting onthe lower air vents 207 of the concrete casks. More specifically,rigidly fixed and forward projecting pawls 112 at the aft base of theU-shaped cask transporter are capable of engaging air vents at thebottom of the spent nuclear fuel cask 120, while locking clamps 200,located high on the structure's forward protruding arms will unfold fromtheir narrow stored position by rotating laterally by their alignmentcylinders 204 and aligning with the cask's center axis 205 and thenextending engagement pads to solidly press the cask walls against hardrubber restraint pads 201, thereby solidly encapsulating the cask. Atwhich point self-locking back up toggle arms 203 will rotate intoposition in close proximity or light contact with the outside edge ofthe cask 120. The toggle locking arms will snap into place, securelydouble-locking the cask into the structure and holding it in the uprightposition without the possibility of tipping forward.

Referring to FIG. 2C, the cask tilt restraint cylinder 200 and the backup toggle links 203 and 206 are shown in a side view to illustrate theirrelative mounting positions high on the cask, and further illustratetheir relationship to the opposing upper and lower solid hard rubberrestraint pads 201.

Referring to FIG. 2D, yet another, and more preferred, air ventengagement 320 is illustrated by engaging the three of the cask's airvents 207 with one center mount lifting pawl 209 and two side-mountlifting pawls 208 for better weight transfer in the cask 120 and thetransporter 102.

Referring to FIG. 3, the power compartment 104 contains a combustionengine 124, generator 126, and alternate shore power connection 128.Other illustrated components of the power compartment include aprocessor 130, an AC electrical panel 132, a CRT display 134 and ahydraulic power unit 140. As an alternative and back-up power source toa combustion engine driven power plant, shore power may be connected tothe electrical panel 132 via the shore power connection 128 to power thecask transporter 100.

Control operations of the cask transporter 100 take place in theprocessor 130. The processor 130 includes a machine logic controller 150to control each of the stack axle assemblies 10 and uniload axleassemblies 106. The machine logic controller 150 includes a steeringmode controller 152 for linear, lateral, diagonal, and rotationalcontrol of the stack axle assemblies 10 and uniload axle assemblies 106.A steering controller 154 is provided to perform multi-axle steeringalgorithm calculations. The steering controller 154 further includes aslew gear motor controller 158 to control the speed and direction of theslew gear motor and a wheel module controller 156 to control the wheelmotors. A suspension controller 160 includes a lift/lower controller 162to lift and lower the transporter 100 and a mean travel heightcontroller 164. An engine/generator controller 166 controls the engine124 and generator 126. The suspension controller 160 providesinteraction between multiple axle assemblies 106 and 10 whilenegotiating undulating surface irregularities along the line of travelof the cask transporter 100. The suspension controller controls thefluid pressure acting on each of the vertical cylinders 18 in the stackaxle assemblies 10 and vertical cylinders 38 in the uniload axleassemblies 106 (FIG. 4).

The stack axle assembly 10 is equipped with an array of sensors 170,including fluid pressure transducers, angularity and lift sensors, wheelspeed sensors which are monitored by a processor 130. The processor 130monitors the loading of each vertical cylinders 18, 38 adds or removesfluid to maintain the loading within the prescribed tolerance for theload being carried, thereby assuring proportional loading across everylift point. It is to be noted that in the case of a plurality of stackaxle assemblies 10 and uniload axle assemblies 106, equalizingsuspension can also be accomplished by dividing the total number ofcylinders 18, 38 into hydraulic line interconnected groups that willallow free interchange of oil between all of the cylinders within agrouping of fluid proportional valves and drive motors.

Further, the information obtained from each of the vertical cylinder's18, 38 pressure transducers allows the processer 130 to calculate andshow on the display 134 the weight and center-of-gravity of the loadbeing carried on a real time basis.

Referring to FIG. 4, the uniload axle assembly 106 includes a drivemotor 14 having mounted thereon a pinion gear 16 in mesh with a ringgear 18 which is bolted to a circular plate as explained hereinafter.The drive motor 14 is bolted to a piston top plate to which is secured asquare machined upper shaft 26 to transmit the torque from the top plateto the wheel set via a square torque plate upper flange 28 which issectional so that it may be removed. A pair of wheels 34 are mounted toaxles which form a relatively fixed part of wheel truck 38 whichincludes a yoke portion. Trunnions 42 are mounted on the sides of thebottom casing which houses a piston secured to the upper shaft 26.Ongoing design versions of the same patent concept eliminate the gearmotor steering for differential steering where all-wheels areelectrically driven with computer controlled differential steering.

Referring to FIG. 5A, illustrated is the adaption of a gantry crane 100configuration, based on two multi-axle sill beams 202 that areinterconnected with a raised center cross beam (204) positioned betweenthe far ends of sill beams 202 and support an interconnecting beam 204which has a raised center portion to allow it to pass over the decks ofheavy haul trailers. The interconnecting beam 204 is also designed witha bolted connection to the sill beams 202 to accommodate field assemblyand disassembly. Interconnecting beam 204 has a bolted center connectionthat will allow an intermediate beam to be bolted in place when a widerstance is required.

FIG. 5B illustrates the omni-directional travel capability andmaneuverability of the stack axle transporter 100. The stack axletransporter 100 can rotate on-center and provide infinitely accuratemaneuvers in linear, lateral, or diagonal travel patterns to alloweffortless precision placement of casks in tight, and otherwisedifficult to access, storage locations.

While stack axle transporters will have higher surface contact pressurethan specialized vertical lift gantry frames attached to crawler tractorbed assemblies, the ability of the stack axle transporter wheelassemblies to independently rotate on center with virtually zero wheelscrubbing action means that the stack axle assembles will not tear theroad surface as do the crawler tracked units. This is particularlyimportant with asphalt road surfaces. The first time a fully loadedstack axle gantry transporter drives on an asphalt road, the stack-axletire loading may compress the asphalt much like the compression of theoriginal roller machines that were used to install the asphalt. A methodto utilize this phenomenon to advantage is the ability, throughprogramming, to have the gantry crane transporter travel in a biasedmanner canted at angle Θ (about 28 degrees) off the travel line A. Thiswill allow the wheels to track on overlapping parallel paths rather thanin single file orientation as shown in FIG. 8. A wide section of theasphalt surface will evenly compress. If the facility will drivemultiple passes they can compress the surrounding asphalt evenly,thereby “rutting” of the asphalt can be turned to an advantage ratherthan a problem. For ISFSI facilities, the travel routes between the fuelbuilding and ISFSI are relatively short and often dedicated to caskhauling.

Referring now to FIG. 5C, one embodiment of a stack axle gantryconfiguration 210 is presented. The center of each sill beam 202 isaugmented with a hydraulic vertical telescoping gantry tower 212. Thehydraulic vertical telescoping gantry tower 212 is rigidly mounted tothe sill beams 202 and penetrates through to within a few inches of theground when the stack axle assemblies 10 are in their lowest positions.A bridge girder 214 is mounted to the top of the hydraulic verticaltelescoping gantry tower 212. In this stack axle gantry configuration,movable lifting devices 216 lift and carry the weights of the liftingdevices 216 and the spreader bar assembly 218. Each movable liftingdevice 216 has spring extended rollers 300, that allow them to be movedacross the bridge girder 214 when not engaged with a heavy load. Eachmovable lifting device 216 will has a monorail-type tractor 220 runningon top of the bridge girder 214. As the hydraulic vertical telescopinggantry tower 212 moves over the first HSM 226 to be placed, the operatorwill activate the monorail-type tractor 220 devices as necessary to bestplace them over the proper points to pick up the HSM 226.

Referring to FIG. 5D, The operation of the single row gantryconfiguration 222 is controlled from an operator's console 224. Theoperator console 224 is used to electronically control the functionalityof the single row gantry configuration 222, specifically the liftingtool 228. In the single row gantry configuration 222, the gantry isstraddling just one HSM 226. The gantry will lower, the lifting straps230 will be threaded through the bottom air vents on the HSM 226, thenlift the HSM 226 for travel to the next position point. The single rowgantry configuration 222 comprises a plurality of stack axle assemblies10 to maximize travel capability and maneuverability of the single rowgantry configuration 222.

Referring now to FIG. 6, a double row gantry configuration 250 isillustrated incorporating the stack axle technology 10. For double rowHSM assembly, the gantry 260 is configured to straddle at least two HSMs226 placed end to end. Typically six to eight or more HSMs 226 areplaced in a single or double line row. The gantry 260 of the double rowgantry configuration 250 is assembled with an extender beam 252 placedin the center between two sill beams. In one embodiment, a longer andheavier capacity bridge beam would connect at least two gantry towers258. The lifting devices 254 and the spreader beam 256 will be free tomove to the center or to one side or the other of the heavier capacitybridge beam for first component assembly, and then precision placing theHSMs 226 in either the left or right hand positions as the double rowmoves forward.

Referring now to FIGS. 7A-7D, another embodiment of the gantryconfiguration 268 is shown which is suitable for both HSM truckoff-loading and HSM assembly configuration. This configuration isnecessary because it is unlikely that the HSMs will be fully assembledprior to final placement. The lifting adapter tool 270 is rectangular inshape and designed for both truck off-loading and HSM assembly. All HSMassembly can be done with the lifting adapter 270 tool in the sameconfiguration needed for truck off-loading. Alternatively, the gantryconfiguration can be changed for placement of HSMs. To change betweentruck off-load configuration 268 and HSM placement configuration 276,the gantry will set the lifting adapter tool 270 on the elevated rack272, then come in again at a 90 degree angle. This action is controlledby the operator from the operator console 274.

Although embodiments have been shown and described directed to atransporter to carry a spent nuclear fuel cask and handling HSMs, thestack axle assembly and transporter utilizing the stack axle assemblymay be used in other applications. Specifically, it would be appreciatedby those skilled in the art that changes may be made in theseembodiments without departing from the principles and spirit of theinvention, the scope of which is defined in the claims and theirequivalents.

1. A stack axle assembly for use in a transporter, comprising: a slewgear; an upper bearing; a lower bearing; a vertical cylinder retained bythe slew gear, upper bearing and lower bearing; an independent driverwheel and idler wheel revolving on a common shaft/trunnion assemblyattached to the bottom of the vertical cylinder; and a frame assemblyformed on top of the vertical cylinder, the frame assembly including oneor more drive motors connecting an upper drive assembly downwardly to adriven assembly mounted between the idler wheel and driver wheel.
 2. Thestack axle assembly of claim 1, further comprising a slew driver motorto drive the slew gear.
 3. The stack axle assembly of claim 1, whereinthe upper bearing includes one or more keyway slots that allow thevertical cylinder to travel vertically, while transmitting rotationaltorque force to the vertical cylinder.
 4. The stack axle assembly ofclaim 1, wherein the driver wheel has a larger diameter than the idlerwheel.
 5. The stack axle assembly of claim 1, wherein the driver wheelis made of a different compressive material than the idler wheel.
 6. Acask transporter, comprising: a main body including a power compartmentand a plurality of uniload axle or stack axle assemblies; two armsextending from the main body, each of the arms including a plurality ofstack axle assemblies; and protrusions formed on the arms and the mainbody to engage a cask.
 7. The cask transporter according to claim 6,wherein the power compartment includes: a power source; a processor; anAC electrical panel; a display; and a hydraulic power unit.
 8. The casktransporter according to claim 7, wherein the uniload axle assembliescomprise: an axle frame including a cylinder housing and hydraulicpiston; and two or more wide faced solid elastomeric wheels on opposingsides of the axle frame, wherein the wheels are on each end of the axleframe and are independently driven by an electric motor.
 9. The casktransporter according to claim 8, wherein the axle frame is centertilting.
 10. The cask transporter according to claim 7, wherein thestack axle assemblies comprise: a slew gear; an upper bearing; a lowerbearing; a vertical cylinder retained by the slew gear, upper bearingand lower bearing; an independent driver wheel and idler wheel revolvingon a common shaft/trunnion assembly attached to the bottom of thevertical cylinder; a frame assembly formed on top of the verticalcylinder, the frame assembly including one more drive motors connectingan upper drive assembly downwardly to a driven assembly mounted betweenthe idler wheel and driver wheel; and a slew driver motor to drive theslew gear.
 11. The cask transporter according to claim 7, wherein theprocessor includes a machine logic controller to control each of theuniload and stack axle assemblies, the machine logic controllercomprising: a steering mode controller to linearly, laterally,diagonally, and rotationally control the uniload and stack axleassemblies; a steering controller to perform steering algorithmcalculations for the plurality of uniload and stack axle assemblies; aspeed/direction controller to provide command signals to the individualuniload and stack axle assemblies; and a suspension controller includinga lift/lower controller to lift and lower the transporter, a mean travelheight controller.
 12. The cask transporter according to claim 11,wherein the suspension controller controls a fluid pressure acting oneach of the hydraulic pistons of each of the uniload and stack axleassemblies to provide interaction between multiple uniload and stackaxle assemblies to negotiate undulating surface irregularities along aline of travel of the transporter.
 13. The cask transporter according toclaim 7, wherein the AC electrical panel includes a shore powerconnection.
 14. The cask transporter according to claim 6, furthercomprising: two sill beams parallel positioned at a predeterminedseparation distance an interconnecting beam positioned to secure the twosill beams in a U-shape; one or more gantry towers mounted in the centerof each sill beam; a bridge girder mounted to the top of the gantrytowers; and at least two movable lifting devices attached to the bridgegirder.
 15. The cask transporter according to claim 14, wherein themovable lifting devices comprise driven tractors positioned on top ofthe bridge girder.
 16. The cask transporter according to claim 15,wherein the driven tractors are controlled by an operator console.